Drier

ABSTRACT

A method of making a drier construction for connection into a refrigeration system is disclosed. The drier construction includes a one-piece body comprising a central cylindrical tubular portion defining a chamber enclosing a desiccant charge with suitable screen and baffle elements. Each end of the body is spun down from the main body by a mechanical spinning process to form stepped tubular extensions. The end of each extension is spun down to form a substantially fluid-tight end closure.

United States Patent Bottum 51 Apr. 18, 1972 [54] DRIER 2,659,128 11/1953 Baldwin, Jr. et al. ..55/387 X [72] Inventor: Edward w Bottum 9357 Spencer 3,407,936 10/1968 Balogh ..210/282 Bnghton 481 16 Primary Examiner-Samih N. Zaharna 22 Filed; b. 17 197 Attorney-Whittemore, Hu1bert& Belknap [21] Appl. No.: 116,095 [57] ABSTRACT A method of making a drier construction for connection into a [52] US. Cl ..210/266,55/387,2l0/282 refrigeration system is disclosed. The drier. construction in- [51] Int. Cl. ..B0ld 27/02, BOld 27/08 cludes a one-piece body comprising a central cylindrical tubu [58] Field of Search ..55/74, 387, 388; 210/266, 282, lar portion defining a chamber enclosing a desiccant charge 210/237 with suitable screen and baffle elements. Each end of the body is spun down from the main body by a mechanical spinning [56] References Cited process to form stepped tubular extensions. The end of each extension is spun down to form a substantially fluid-tight end I UNITED STATES PATENTS Closure.

2,405,201 8/ 1 946 Franck ..210/282 X 5 Claims, 5 Drawing Figures DRIER BACKGROUND OF THE INVENTION Driers are commonly utilized in refrigeration systems to purify the refrigerant charge flowing through the system. The drier contains a desiccant material, which may be provided in many different forms, to remove undesired moisture from the refrigerant charge. Such driers also usually contain a screen or strainer to remove foreign particles from the refrigerant charge.

The present invention provides a drier construction which may be connected to different tube sizes commonly found in refrigeration systems. The adaptability of the drier construction to different tube sizes reduces the inventory which must be carried by the servicing technician. Thisadaptability is accomplished by stepping down the diameter of an extension which projects from each end of the main drier body. The extensions may be cut off at the desired point to fit different size tubing found in a refrigeration system.

The entire drier body is fabricated from a single length of cylindrical tubing. This is accomplished by mechanically spinning down the ends of the raw tubing into the desired stepped configuration. Additionally, the ends of the extensions are turned radially inwardly and,'as a result of theheat generated during the spinning process, the ends merge together to form fluid-tight closures. This desirably hermetically seals the interior of the drier during storage so that the desiccant will stay dry indefinitely. The provision of plastic sealing caps or brazed ends to seal the interior of the drier, as has been done in the past, is eliminated. If, in a particular processing technique of the present invention, the ends of the extensions are not entirely closed so as to be fluid-tight with respect to the pressures to be encountered during storage, they will still be closed sufficiently to permit complete sealing by coating the ends with a thin layer of a sealant material. The absence of the use of heat during the fabrication of the drier eliminates the need for wire brushing or other finishing after the manufacturing process. Such wire brushing and finishing are frequently used to improve the appearance of the unit. The present process is economical and results in reducing the cost of the final product.

SUMMARY OF THE INVENTION A method of making a drier construction for connection into a refrigeration system is provided. The method comprises the steps of providing a cylindrical tubular member of a predetermined length. A desiccant charge is then placed within the tubular member and is positioned centrally thereof. Each end of the tubular member is then mechanically deformed under pressure and heat conditions by the metal spinning process into a shape forming a final article comprising a central cylindrical portion defining a chamber which encloses the desiccant charge, the chamber having a tubular expansion extending longitudinally outwardly from each end thereof. Each extension is formed into at least first and second portions. The first portion extends from the central chamber portion and is of reduced diameter with respect thereto. The second portion extends from the first portion and is of reduced diameter with respect theretov The outer tip of the second portion is turned radially inwardly to form a closed substantially fluid-tight end closure.

IN THE DRAWING device into the desired configuration; and

FIG. 5 is a longitudinal sectional view of a completed drier.

The type of drier to which the present invention relates finds normal use in refrigeration systems. The basic function of such driers is to remove moisture from the refrigerant charge in a closed refrigeration system. Another function of the drierof the present invention is to also remove foreign particles which find their way into the stream of refrigerant in a system. Such particles may occur as the result of breaking away of .very small metallic particles from the various metallic components and tubing forming the circuitry of the system. Foreign particles may also enter the system from an exterior source when the system is opened for servicing.

The casing for the drier 10 is formed from a length of tubing 12. The tubing 12 has an interior diameter of a size equal to that desired in the final product. The center portion of the tubing 12 is used as a compartment for the reception of desiccant material andfor reception of an inlet baffle 16 and an outlet screen 18. The ends of the tubing 12 are formed into stepped extensions of smaller diameter than the center portion and are utilized for connecting the drier to the conduits of a refrigeration system. The tubing 12 is preferably of a metallic material such as copper. In the first step of the invention, tubing 12 of the desired length is provided. Ordinarily, the tubing 12 is cut from a longer piece oftubing. The length of the tubing 12 is somewhat less than the final length of the drier 10 because during formation of the drier, the ends of the tubing are reduced with a resultant increase in the overall length thereof. An arrow 14 is formed on the exterior of the tubing 12. The arrow 14 indicates the direction of flow of refrigerant through the tubing. This arrow aids in assembly of the device in that it informs the worker where the baffle and screen are to be placed. Additionally, in use of'the drier 10 by a technician in the field, the-arrow 14 will inform the technician as to which end should be connected downstream and which end upstream of the refrigerant circuitry.

After the tubing 12 has been formed, a cup-shaped perforated bafile 16 is placed within the tubing at the inlet end and a basket-shaped screen 18 is placed at the outlet end. A charge of granular desiccant material 20 is positioned between the baffle 16 and screen 18. The desiccant 20 may be provided in the granular form illustrated or other forms may be utilized such as a moldeddesiccant block or a bag filled with granular material. 1

Placement of the baffle 16 and screen 18 is important. The baffle 16. includes an outer annular wall 22 which forms a press fit with the interior surface of the tubing 12. Similarly, the basket-screen 18 includes an annular rim 24 to which the screen structure is attached. The rim 24 also forms a press fit with the interior surface of the tubing thus fixing the location of the screen and baffle after they have been inserted either automatically or manually. If inserted manually, a tool is provided for engagement of the elements, the tool being provided with a measuring gauge to facilitate insertion of the elements the proper distance into the tubing. As will be noted, portions 26 and 28 of the tubing extend from the baffle 16 and screen 18, respectively. These portions are ultimately formed into the stepped ends of the drier.

After the assembly of FIG. 2 has been made, the ends of the tubing are subjected to a metal spinning process to form the desired stepped configuration thereof. The spinning process is illustratively a two-stage process as illustrated in FIGS. 3 and 4. However, depending upon the desired final configuration of the ends of the drier, the spinning process may be either a one step or more than a two step process.

The mechanics of the spinning process is conventional, a representative technique for such spinning being disclosed in U.S.'Pat. No. 2,313,474. In the spinning process, the ends 26, 28 of the tubing 12 are fashioned to the contour of tools 30, 32 by exerting a reducing pressure on the tubing as the tubing and tools are relatively rotated and moved in directions toward each other.

Each of the tools is provided with a continuous annular portion 34, 36 which gradually decreases in cross-section and exerts a reducing pressure continuously around the entire circumference of the ends of the tubing 12 to progressively heat the ends to a plastic and easily workable condition.

The portions of the tubing leaving the annular heating portions 34, 36 enter a cavity 38, 40 also formed in the tool. The cavities have a portion which progressively decreases in crosssection longitudinally of the tool. This portion of the cavities is formed with a relief recess 42, 44 which extends longitudinally substantially throughout the length of the cavities and has an area which is relatively small as compared to the area of the tubing confining wall portion of the cavities. As a result, the wall portion of the cavities exerts a reducing pressure on a continuous area extending over the major portion of the circumference of the tubing and the remaining portion of the tubing is free to deform into the relief recess in response to the reducing pressure.

As a result of providing the relief area, seizure between the tubing and the tool due to thermal expansion is eliminated and the excess metal resulting from the reduction in cross-section of the tubing is accommodated and allowed to remain in a plastic state but is not overheated. The reduction continues in accordance with the confining portion of the tools and in accordance with the shape of the tools until it is arrestedby either discontinuing the operation of the tools or by a positive stop. The method may be used either in connection with metallic or non-metallic materials.

Referring more specifically to FIG. 3, the first stage of forming of the end 28 involves relatively rotating the tool 30 and tubing 12 while forcing the tubing into the opening in the tool. As above described, the tubing heats up and is formed into the shape illustrated in FIG. 3. As will be noted, the end portion 28 is configured into a radially inwardly curved portion 46 extending from the main body of the tubing and an elongated portion 48 of smaller diameter than the tubing 12. The end surface 50 of the tool serves as a stop surface to limit movement ofthe tubing into the tool.

As shown in FIG. 4, the outer end of the reduced diameter portion 48 is then inserted into the second tool 32. A second radially inwardly directed curved portion 52 is formed and extending therefrom is a second elongated portion 54 which is reduced in diameter with respect to the portion 48. The cavity 40 has a second portion 56 at the end thereof which progressively decreases in cross-section longitudinally of the tool. This portion extends up to the center of the tube portion 54 to thus cause the tip 58 of the tubing to be directed radially inwardly and close upon itself thus forming a closed end.

It has been found that the closed end of the tubing is substantially fluid-tight and is capable of withstanding fluid pressures in the range of from to pounds per square inch above atmospheric pressures. The plastic condition of the hot metal during the spinning process causes the end of the tubing to close in the fluid-tight fashion. The material tends to flow and weld together. Thus, for all intents and purposes, the interior of the tubing is made air-tight. This prevents the ingress of moisture or other contaminants from the ambient atmosphere during storage of the drier.

If it is desired to improve the seal at the ends of the tubing, a thin layer 60 of a plastic sealant material may be applied as illustrated in FIG. 5. The plastic material may be any of a variety of such materials having sealing properties. It may be applied by dipping, brushing or like conventional techniques.

The spinning process as illustrated in FIGS. 3 and 4 may be applied to each end of the tubing simultaneously or successively.

The final drier 12 is illustrated in FIG. 5. As will be noted, the center portion 62 contains the desired desiccant 20, baffle l6 and screen 18. Projecting longitudinally outwardly from the center portion 62 are the end portions each of which comprises a first section 48 having a reduced diameter with respect to the diameter of the center portion 62 and a second portion 54 having a reduced diameter with respect to the portion 48. Representatively, the portion 48 may have a diameter of three-eighths inch while the portion 54 may have a diameter of one-quarter inch to fit the standard tubing generally utilized in refrigeration systems.

In order to connect the drier 10 to a %-inch tubing, the portion 54 is severed from the portion 48 at a point just inwardly of the curved portion 52. In order to connect the drier 10 to tubing of one-half inch diameter, tht tip 58 is severed from the portion 54. The drier may be adapted for connection to capillary tubing which is of relatively small diameter. This may be accomplished by severing a portion of the tip 58, inserting the capillary tubing through the opening thus formed and then deforming the end of the portion 54 to fit around the capillary tubing as by use of pliers or a tube forming block. Similarly, tubing of an intermediate size having a diameter smaller than the portion 54 or a diameter smaller than the portion 48 may be connected to the drier 10 by deforming either the portion 48 or portion 54 as the case may be by means of a tube forming block or pliers to fit the intermediate size tubing. It will be appreciated that in the above discussion of tube sizes, the sizes are merely exemplary and the drier may be manufactured to fit various different sizes of tubing.

What I claim-as my invention is:

l. A drier construction for connection into a refrigeration system comprising a one-piece body including a central portion defining a cylindrical tubular chamber, a desiccant charge in the chamber, a perforated baffle in the chamber on the upstream side of the desiccant charge and a screen element in the chamber on the downstream side of the desiccant charge, said baffle and screen functioning to maintain the charge in the desired position, a cylindrical tubular extension extending longitudinally outwardly from each end of the chamber, each extension comprising at least first and second portions, the first portion extending from said central portion and being of reduced diameter with respect thereto, the second portion extending from the first portion and being of reduced diameter with respect thereto, and the outer tip of the second portion being turned radially inwardly to form a closed, substantially fluid-tight end closure.

2. The method of making a drier construction for connection into a refrigeration system comprising the steps of providing a cylindrical tubular member of a predetermined length, placing a desiccant charge within the tubular member and positioning the charge centrally of the member, then mechanically deforming each end of the tubular member under pressure and heat conditions by the metal spinning process into a shape forming cylindrical tubular extensions extending from the central portion of the tubular member which thereby defines a chamber for the desiccant charge, each of said extensions being formed into a shape comprising at least first and second portions, the first portion extending from said central portion and being of reduced diameter with respect thereto, the second portion extending from the first portion and being of reduced diameter with respect thereto, and spinning the outer tip of the second portion radially inwardly to form a substantially closed end.

3. The method as defined in claim 2, further characterized in that the step of mechanically deforming each end of the tubular member is accomplished in two stages, the first stage comprising deforming each end into an extension having a diameter equal to the diameter of said first portion, the second stage comprising deforming the outer portion of said extension into said second portion and spinning the outer tip of the second portion radially inwardly to form said substantially closed end.

4. The method as defined in claim 2, further characterized in providing a sealant coating on said closed ends to further seal the ends.

5. The method as defined in claim 2, further characterized in the press-fitting of a perforated baffle on the upstream side of the desiccant charge and press-fitting a basket-type screen element on the downstream side of the desiccant charge to thereby positively position the charge centrally of the tubular member. 

1. A drier construction for connection into a refrigeration system comprising a one-piece body including a central portion defining a cylindrical tubular chamber, a desiccant charge in the chamber, a perforated baffle in the chamber on the upstream side of the desiccant charge and a screen element in the chamber on the downstream side of the desiccant charge, said baffle and screen functioning to maintain the charge in the desired position, a cylindrical tubular extension extending longitudinally outwardly from each end of the chamber, each extension comprising at least first and second portions, the first portion extending from said central portion and being of reduced diameter with respect thereto, the second portion extending from the first portion and being of reduced diameter with respect thereto, and the outer tip of the second portion being turned radially inwardly to form a closed, substantially fluid-tight end closure.
 2. The method of making a drier construction for connection into a refrigeration system comprising the steps of providing a cylindrical tubular member of a predetermined length, placing a desiccant charge within the tuBular member and positioning the charge centrally of the member, then mechanically deforming each end of the tubular member under pressure and heat conditions by the metal spinning process into a shape forming cylindrical tubular extensions extending from the central portion of the tubular member which thereby defines a chamber for the desiccant charge, each of said extensions being formed into a shape comprising at least first and second portions, the first portion extending from said central portion and being of reduced diameter with respect thereto, the second portion extending from the first portion and being of reduced diameter with respect thereto, and spinning the outer tip of the second portion radially inwardly to form a substantially closed end.
 3. The method as defined in claim 2, further characterized in that the step of mechanically deforming each end of the tubular member is accomplished in two stages, the first stage comprising deforming each end into an extension having a diameter equal to the diameter of said first portion, the second stage comprising deforming the outer portion of said extension into said second portion and spinning the outer tip of the second portion radially inwardly to form said substantially closed end.
 4. The method as defined in claim 2, further characterized in providing a sealant coating on said closed ends to further seal the ends.
 5. The method as defined in claim 2, further characterized in the press-fitting of a perforated baffle on the upstream side of the desiccant charge and press-fitting a basket-type screen element on the downstream side of the desiccant charge to thereby positively position the charge centrally of the tubular member. 